I am a Medical Imaging Technologist & it's now extremely rare to have an adverse reaction to the contrast medium; especially since they no longer use iodine. People whose kidneys are damaged might possibly have been going into kidney failure. There is no radiation danger. There are intensifiers that expand a very tiny dose of x-ray. I myself am in Kidney failure, but precautions were taken prior to my 5 angiograms & angioplasties. I have 4 stents. no problems with adverse effects. They saved my life.

I was called in early for rehydration drip for 14 hrs before 2nd stent procedure 5 weeks after 1st stent + heart attack. I have Ckd I went in hospital as emergency they didn't know I had CKD. My filtration rate was really low.Not hospitals fault but was told I have Renal impairment now Gfr between 25/35 prior was 43. They did their best.

My gfr was low 16, was toxic and dehydrated prior.

I'm a retired (for 6 months) Medical Imaging Technologist. I'm not sure where you live, but there's no risk to the contrast medium (lay-people call it dye) used here in Canada or the USA. In the old days when iodine was part of the mix allergic reactions could happen, but usually it was established beforehand if the patient is allergic to iodine & tests using contrast mediums with iodine would not be chosen. Also, the radiation dose in ANY diagnostic testing has not been a concern for many, many years if modern up-to-date x-ray equipment is being used. A miniscule amount of radiation is being used with image intensifiers, so the radiation dose is insignificant. Something to consider: -- sometimes it could be said that NOT doing the test is dangerous.

I'm no expert, but I needed a cat scan and the required blood work showed that I could not have the dye. Luckily for me, they did it without the dye and learned I was having a big problem with a medicine that needed to be stopped.